Actuating device for bridging-levers of sawmills.



No. 747,161. PATENTED DEC. 15, 1903. J. A. GILLARD.

AGTUATING DEVICE FOR BRIDGING LEVERS OF SAWMILLS.

. APPLICATION FILED JAN. 19. 1903.

Fig- 1 N0 MODEL. 3 SHEETS-SHEET 1.

fl/Zfneases.

No. 747,161. PATENTED DEC. 15, 1903.

J. A. GILLARD.

ACTUATING DEVICE FOR BRIDGING LEVERS 0F SAWMILLS.

APPLICATION FILED JAN. 19, 1903. 7

N0 MODEL, 3 SHEETS-SHEET 2v PATENTED DEC. 15, 190.3. J. A GILLARD. AGTUATING DEVICE FOR BRIDGING LEV-HRS 0F SAWMILLS.

APPLICATION FILED JAN. 19. 1903.

3 SHEETS-SHEET 3 N0 MODEL.

(we wm g llmrinn Fmarns Patented December 15, 1903.

,ATENTT FFlQF.

ACTUATING DEVICE FOR RIDGlNG LEVERS OF SAWMILLS.

SPECIFICATION forming part of Letters Patent No. 747,161, dated December 15, 1903.

Application filed January 19, 1903. Serial No. 139,519. (No model.)

To aZZ whom it may concern.-

Be it known that I, JOSEPH A. GILLARD, a citizen of the United States, residing at Minneapolis, in the county of Hen nepin and State of Minnesota, have invented certain new and useful Improvements in Actuating Devices for Bridging-Levers of Sawmills; and I do hereby declare the following to bee full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to sawmills, and is especially directed to improved means for actuating the so-called' bridging-levers which bridge over the space between the log-deck and the carriage and deliver the logs from the former to the latter over the lumber-conveyer.

The invention consists of the novel devices and combinations of devices hereinafter described, and defined in the claims.

The invention is illustrated in the accompanying drawings, wherein like characters indicate like parts throughout the several vertical section taken on the line 00 x of.

Fig. l.

The numeral 1 indicates the floor-beams, the numeral 2 the log-deck, the numeral 3 one of the rails of the carriage-track, the numeral 4 one of the lumber-conveying rollers, and the numeral 5 the logcarriageof an ordinary sawmill.

The characterz indicates logs, one of which in Fig. 2 is indicated by dotted lines.

The character a indicates bridging'levers, of which, as shown,- there are two. These bridging-levers a are rigidly secured on a rock-shaft a, suitably journaled in hearings on the upper delivery portion of the log-deck 2. As shown, the hubs of the bridging-lever a have segmental extensions 0, which constitute combined log stops and kickers.

Mounted in suitable bearings b, shown as secured on the floor-timbers 1,is another rockshaft b, which is provided with arms 6 connected to the respective segments a by conordinary or any suitable way.

engine.

parts of the connections.

nectingrods 19 The arms 11 and connected rods 12 constitute toggles, as will presently be noted. The rock-shaft b is further provided, preferably at its intermediate portion, with an arm 6 which is connected by a rod 5 to the piston-rod c of a straight-line reciprocating engine a, which is preferably actuated by steam in the ordinary way. The said engine 0 would be rigidly supported in the (Not illustrated.)

As hitherto constructed, bridging-levers similar to those illustrated in the drawings have been actuated by a straight-line reciprocating engine, the piston of w hich has been so connected to the said bridging-levers that when the latter are thrown down to deliver the logs to the log-carriage the great weight of the logs was sustained only by the pressure of the steam within the cylinder of the Under this pressure of the logs on the bridging-levers under the arrangement just noted the steam is frequently so highly compressed in the upper end of the cylinder of the actuating-engine that the cylinderhead has been blown out and sometimes such cylinder-head has been directly crowded off by having the piston forced against the same.

As the principal feature of my invention I so arrange the connections between the bridging-levers and the piston of the engine that when the said levers are thrown down, so as to deliver the logs to the carriage, the Weight of the logs will not be sustained or resisted by the engine, but will be taken by This will become clear by noting the different positions of the parts shown in Figs. 1 and 2. Fig. 1 illustrates the normal positions of the parts, wherein the bridging arms or levers are thrown upward to hold back the logs from the log-deck. The piston of the engine is then of course thrown downward to its limit and the toggle afiorded by the arm I) and rod 19 is buckled. It is also evident that the bridging-levers are thrown pivotally downward, so as to span the space between the log-deck and the carriage and deliver one of the logs from the former to the latter when the piston of the engine is forced upward. In this position of the parts (see Fig. 2) it will now be noted the toggle stands on a dead-center with the shaft b, so that the weight of the log on the bridging-levers is thrown entirely upon the said shaft 1). It is furtherobvious thatin the above-noted position of the parts the weight on the bridging-levers will have no tendency whatever to force further upward the piston of the engine. Hence of course there is no danger of the piston-head being thrown into contact with the upper cylinder-head or that abnormally high pressure will be produced in the cylinder.

From what has been said it will of course be understood that the device above described is capable of considerable modification within the scope of the invention herein set forth and claimed. However, the actuating connections between the piston of the engine and the bridging-levers, involving a toggle, such as that aiforded by the arm 19 and rod 19 and a thrust-shaft, such as that afforded by the shaft 1), constitute the simplest and most efficient device which I have so far been able to devise for the purpose had in view.

What I claim, and desire to secure by Letters Patent of the United States, is as follows:

1. In a sawmill, the combination with pivoted bridging-levers and a reciprocating engine, of a connection between the piston of said engine involving an intermediate thrustshaft and a toggle, which toggle, when the bridging-levers are thrown down to deliver a log to the log-carriage, stands on a dead-center with respect to said thrust-shaft, thereby throwing the strain from the weight of the log onto said thrust-shaft, substantially as described.

2. In a sawmill, the combination with the log-deck,acarriage and a straight-line reciprocating engine, of a rock-shaft a mounted on said deck and provided with bridginglevers a and segments a", the thrust-shaft I) mounted in fixed bearings and provided with arms 6 connected by rods 6 to the corresponding segments a said elements b b constituting toggles, and the arm b on said shaft 5 connected by a rod to the piston of said engine, which toggles 12 17 when the bridge lovers are thrown down, stand on a dead-center with respect to said thrust-shaft 1), substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

JOSEPH A. GILLARD. Witnesses:

HERBERT G. MILLER, O. HENNINGSEN. 

